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Not much of an update but here goes

Got many plans, and little time to get everything done. The story of my life. he he

Anyways… My journey with the ffmpeg API has now taken another turn. Now I’m travelling the realm of using the AVIOContext. This is because I need to temporarily store a UDP transport stream locally when a pause of playback is required. Before the weekend I was non the wiser of how to do this, but after a good think about it, sorted.

All I need to do is to join the multicast stream manually, grab the packets, buffer them up and when ffmpeg, via the AVIOContext requests data, just send it. Simple. One problem I’ve yet to face is that after a pause, I want to be able to seek through the saved stream. I’ll come to that.

As for my own stuff. I’m kind of halfheartedly putting my feet up. I really need to put my feet up properly actually but I’ll take what I can get.

WebGL interactive

Nothing to show yet because it would be quite dull, but I’ve got mouse movement and click interaction working in the 3D scene. Basically, if the mouse clicks an object (when it’s not occluded) it will do stuff. And when the mouse hovers over an object. Old school really, but for WebGL, this can demonstrate a lot.

And at this time of night, I’m goosed.

WebGL Demos

Okay, a new page WebGL Demos has been added. So far these have just been knocked up in CopperCube using the CopperLicht WebGL 3D engine. Very easy to use and for demonstration purposes, good for eye candy shows.

 

I’ve always tried hard to stay away from HTML, CSS and Javascript because I never saw the point when I’m a programmer that can do so much more than front end web stuff.

As time goes by I will be showcasing other engines such as LibGdx and Parallax3D.

So keep your eyes peeled…

A quick faff about

Faffing about with libGDX tonight, all in Java, I’ve realised yet again how simple it can be setting up sh.. stuff in Java.

I went straight into the 3D scene, two new classes, one as a controller for a demo scene setup and the first scene. The controller just does the timing which does zip at the moment. The second class is the ‘Screen’ which sets up my first screen. Really simple. A camera,  a cube and a simple motion.

I had to stop because of the time tonight. I really wanted to faff around with the mesh builder again and custom shaders. Gonna be some time before I produce those screens, but that’s coming up.

Lesson learnt at my first Hackathon

At the Sprint24 Hackathon in Liverpool at Ziferblat I learned a lesson fast. My dietary needs and health come first over trying to do what everyone else is doing.

I’d already prepared myself by taking the necessary tablets with me in case of a minor hiccup, ie they had normal milk. But this wasn’t enough.

The team I was with at first had a great web interface designer and had no problems knocking up pages for the challenge we took. Two drinks of coffee and a smidgen of a dash of milk. One tablet to counter.

A few hours in and I was on my own. At that point I’d had two cans of fizzy ‘zero’ cans of pop. During the second can I took another tablet. I wasn’t feeling too good.

Whilst I was on my own and feeling rough on the inside, I starting to feel like I wasn’t getting anywhere, when one of the organisers came over. I explained my team had gone and that I had reservations as to whether they would be back, which they had told me would be tomorrow morning. This was about 4pm’ish. The organiser, I can’t remember his name but remember what he looked like, said he would hook me up with another team.

Very shortly after I was hooked up with another team and paired with the youngest of the team. A very smart lad he was and understood a hell of a lot. And a surprisingly enough, a very quick learner. We got on with investigating the challenge.

And then, pizza turned up. Which was my downfall. It was only one slice of pizza that took everything out of me.

Because of what the effects where to my body, and with everyone around me snacking continuously, I couldn’t speak out about what it was. Although the truth I did say, was I was zapped of energy and getting tired.

I also know that there’s alcoholic drinks I can’t have. One of them being lager. I must’ve had two before I realised for certain that there was no coming back from this. Two light beers would normally have no effect me. This was all adding up

All I did, was keep smiling the best I could. My brain had shut down on me and my normal mode of focus was shot too hell. Try as I did, I couldn’t get my body from feeling so rough and lethargic. I had to eventually tell the team I was calling it a day and going home. I’d rather tell them that rather than say I would be back in the morning and not turn up.

The day before, the missus had bought in some stuff that she would have prepared for me for this event, but I turned it down. These were all on my safe to eat and drink list and would’ve lasted more than two days.

Lesson: It’s not good for your health trying to fit in. Especially when you cannot eat or drink what’s to hand, when there’s a supermarket just down the road.

It’s 2am, I’m at home and I’ve not started to recover yet.

Good luck to all at Ziferblat Sprint24 Hackathon

Perseverance and a nice win

I’ve already got the media manager software completed, although it will get a huge face lift in the near future. I’ve also got a running server that at the moment does quite a lot of things. I’ve also got the player on the devices making solid connections. New devices show up in the file system and internal databases. All the servers responses are currently 100%.

Tonight, I got my android app communicating with the server. After a silly mistake, the app now fetches new devices from the server and displays them ready for the next step. All connections are completely over the internet and via TCP. Eventually, once all test have been completed, all the security will be put into place. I’m not even thinking about security just yet because the later I leave it before the final product, the more secure it will be.

Actually, that very last sentence has just got me thinking about security. I seriously need to start securing this right now. Tomorrow I will implement the initial security layer (which is configurable).

Still no code snippets, sorry.

And still a fair bit of work to get done.

10 PRINT "HELLO WORLD"
20 GO TO 10

Personal project update Wed 20/09/17

The player software I am writing which had a big refactor last night now sends its unique ID to the server. The server also now stores this without a playlist which can be picked up by the mobile application which I started last week, but tomorrow I will work on.

At the moment, the server does actually look through the internal database and responds to the client, which is working so far. At the moment it just responds with a zero playlist and closes the connection.

I was too busy to be adding the encryption which can actually wait for now.

The next step is to get the Android software to be able to create temporary playlists, pick up empty devices, duplicate other devices playlists and set a new device up. Just this bit will take a little while because the Android API is quite huge and I’m used to using Qt, not Android Studio.

What I ought to be doing, which is what I do at work, is to keep a progress diary. I’ll make a start on that now actually. This I can update every time I work on my own projects.

I’m happy with the progress so far because even though I get a maximum of 2 hours after work and maybe a little bit more at the weekends, this particular project is taking shape finally.

There will be one main PC piece of software that will control everything as well as a few Android apps that do their bits. The devices player and the server are the easy bits. Although through time, I’ll have to look at making this scalable.

Project update (no code snippets tonight)

My personal project has taken a huge face lift. The original player code has been stripped and split into two classes, the media client layer and the player itself.

The media client is the heart of the player which handles the communication with the server and supplies the player with its playlist. It’s still not compete by far, but closer to what I need it to do.

The player at the moment does zip all. The intention is to have it playing a media file and then check with the media client of any updates which will adjust it’s playlist. All previous tests of the media player have been running great.

The android app is still waiting on the above media client and its communication with the server so that I can move that one forward.

Basically tonight has been refactoring a lot of code. With a lot of testing in between. So far so good, but I’ve run out of time for tonight. Two hours isn’t enough.

I’ll need some time to do some Blender work soon also.

Cryptography Secure TCP Sockets in Java

Well, I finally got round to testing out a basic encryption over TCP sockets.

First off, the main() entry looks very familiar and is easy to understand. I simply create the listening server (doesn’t spawn thread for simplicity), with the ability to safely shut it down.

Then I use the DataInputStream and DataOutputStream to send data back and forth. In this test case I sent a string which both the client and server will print to the console.

Once that was working, I extended the OutputStream and InputStream and override the read() and write() methods (shown in the code examples below). Notice that I manipulate the byte in two different ways, one by adding and subtracting and the other by XOR’ing (commented out but works). If these manipulations match up whilst data is being sent back and forth then there’s no errors.

Main class

The main class and entry point to the test which spawns the server and then runs a couple of tests:

package com.wlgfx.cryptotest;

public class CryptoServer {

    public static void main(String[] args) {
        WLCryptoServer server_run = new WLCryptoServer();
        Thread server = new Thread(server_run);
        server.start();
        
        System.out.println("Server thread started");
        
        new Thread(new WLCryptoClient("Hello world!")).start();
        
        try { Thread.sleep(500); } catch (InterruptedException ex) {}
        
        new Thread(new WLCryptoClient("Jump around and stomp your feet!")).start();
        
        try { Thread.sleep(500); } catch (InterruptedException ex) {}
        
        server_run.quitServer();
    }
}

Server class

The server code which take the input and output streams and creates new subclasses of the encryption layer classes and then creates the usual DataInputStream and DataOutputStream for the rest of the normal IO. This matched in the following code for the client.

package com.wlgfx.cryptotest;

import com.wlgfx.cryptotest.WLC.WLInputStream;
import com.wlgfx.cryptotest.WLC.WLOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

public class WLCryptoServer implements Runnable {
    
    private final int port = 1999;
    private boolean quit = false;

    @Override
    public void run() {
        try {
            ServerSocket socket =  new ServerSocket(port);
            socket.setSoTimeout(1000);
            
            while (!quit) {
                Socket client = socket.accept();
                
                WLOutputStream wlout = new WLOutputStream(client.getOutputStream());
                DataOutputStream out = new DataOutputStream(wlout);
            
                WLInputStream wlin = new WLInputStream(client.getInputStream());
                DataInputStream in = new DataInputStream(wlin);
                
                String text = in.readUTF();
                System.out.println("SERVER: " + text);
                out.writeUTF(text);
                
                client.close();
            }
        } catch (IOException ex) {
            System.out.println("SERVER: " + ex.getLocalizedMessage());
        }
    }
    
    public void quitServer() {
        quit = true;
    }
}

Client class

The client code is just the same as the server class code.

package com.wlgfx.cryptotest;

import com.wlgfx.cryptotest.WLC.WLInputStream;
import com.wlgfx.cryptotest.WLC.WLOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;

public class WLCryptoClient implements Runnable {
    
    private String text;
    private Socket socket;
    
    private final int port = 1999;
    
    public WLCryptoClient(String test) {
        text = test;
    }
    
    @Override
    public void run() {
        try {
            socket = new Socket("localhost", port);
            
            WLOutputStream wlout = new WLOutputStream(socket.getOutputStream());
            DataOutputStream out = new DataOutputStream(wlout);
            
            WLInputStream wlin = new WLInputStream(socket.getInputStream());
            DataInputStream in = new DataInputStream(wlin);
            
            out.writeUTF(text);
            text = in.readUTF();
            System.out.println("CLIENT: " + text);
            
            socket.close();
        } catch (IOException ex) {
            System.out.println("CLIENT: " + ex.getLocalizedMessage());
        }
    }
    
}

The encryption class

This is where you can see exactly how easy it is to manipulate the data being sent back and forth.  Here I am showing you two methods, XOR and add and subtract. It’s very simple, but for heavier encryption you could look further at CSPRNG, or Crypto Secure Pseudo Random Number Generator. PRNG’s are ten a penny, from simple ones to hefty things. Take your pick. The Crypto and Secure layers are the ones you really need for truly undecipherable data communication.

package com.wlgfx.cryptotest;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class WLC {

    // NB: short inner classes are static to avoid errors
    
    public static class WLInputStream extends InputStream {

        private InputStream in;

        public WLInputStream(InputStream input) {
            in = input;
        }

        @Override
        public int read() throws IOException {
            byte a = (byte) in.read();
            a--;
            return (int) a;

            //return in.read() ^ 255; // WORKS TOO
        }
    }

    public static class WLOutputStream extends OutputStream {

        private OutputStream out;

        public WLOutputStream(OutputStream output) {
            out = output;
        }

        @Override
        public void write(int b) throws IOException {
            byte a = (byte) b;
            a++;
            out.write((int) a);

            //out.write(b ^ 255); // WORKS TOO
        }
    }
}
Console output: 
run:
Server thread started
SERVER: Hello world!
CLIENT: Hello world!
SERVER: Jump around and stomp your feet!
CLIENT: Jump around and stomp your feet!
SERVER: Accept timed out
BUILD SUCCESSFUL (total time: 1 second)

Until next time

😛

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